Underground electric conduit



1 (No Model.)

J. DELL. UNDERGROUND ELECTRIC GONDUIT.

No. 417,992. Patented Dec. 24, 1889.

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UNITED STATES PATENT OFFICE.

JOHN DELL, OF ST. LOUIS, MISSOURI.

- UNDERGROUND ELECTRIC CONDUIT.

SPECIFICATION forming part of Letters Patent No. 417,992, dated. December 24, 1889.

Application filed August 20, 1889. Serial No. 321,404. (No model.)

To all whom it may concern.-

Be it known that 1, JOHN DELL, of the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Conduits for Electric Conductors, of

. which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification. I

My improvement relates to a peculiarlyconstructed terra-cotta, vitrified, or cement wall of the conduit, forming an annular series of passages surrounding the central passage.

Figure I is a perspective view of the device, showing the central passage octagonal in transverse section and the conduit round on the outside. Fig. II is a transverse section of same. Fig. III is a transverse section showing the central passage hexagonal in transverse section and the outside of the same form. r

1 is the outside or outer wall of the conduit.

At 2 is shown the central passage, which is I means for connecting the sections of the conduit together in line, any suitable means being used for this purpose.

It is intended to make each section of the conduit in one piece, all the parts 1 3 5 being integral; but I do not regard it as essential that the parts of the conduit-section should be integral.

I have shown the central passage as octagonal in Figs. I and II and hexagonal in Fig. III but I do not confine myself to these numbers of sides in the passage.

I claim as my invention- 1. A conduit for electric wires, made of earthy material and having a central passage polygonal in transverse section, with walls 5 extending radially from the angles 4 of the central passage to the outer wall 1 of the cona similar polygonal outer shell having its sides parallel to the sides of the inner shell, and walls radiating from the angles of the inner shell and supporting the outer shell at its angles, substantially as and for the purpose set forth.

JOHN DELL. In presence of BENJN. A. KNIGHT, E. S. KNIGHT. 

